A conventional vehicle bumper structure in which, in order to absorb the impact of a vehicle collision, a cushioning member is provided at the rear of a rear bumper beam, and the rear bumper beam and the cushioning member are covered by a rear bumper cover (rear bumper face) is proposed in Japanese Patent Laid-Open Publication No. 2002-264740, for example. This bumper structure will be described with reference to FIG. 8.
A vehicle bumper structure 100 shown in FIG. 8 includes a rear bumper beam 103 extending transversely of a vehicle at a rear end 102a of a side member 102 in a rear part 101 of the vehicle body, a cushioning member 104 provided at a rear portion 103a of the rear bumper beam 103, and a rear bumper face 105 covering the rear bumper beam 103 and the cushioning member 104.
When the vehicle collides with a wall (not shown) or the like, for example, the bumper structure 100 absorbs the collision energy with the rear bumper beam 103 crushed via the cushioning member 104.
Recently, with the object of improving automobile design, some rear bumper faces have a rear lower portion narrowed down and formed in a forward curved shape. To adapt the rear bumper beam 103 shown in FIG. 8 to such rear bumper faces, it is necessary to make a rear lower portion 103b of the rear bumper beam 103 conform to such rear bumper faces.
An example of this configuration will be described with reference to FIG. 9.
Referring to FIG. 9, a rear lower portion 110a of a rear bumper face 110 is narrowed down and formed in a forward curved shape. Therefore, it is necessary to recess a rear lower portion 111a of a rear bumper beam 111 in a forward direction of the vehicle body in conformity with the rear lower portion 111a of the rear bumper face 110.
A rear upper portion 11b of the rear bumper beam 111 protrudes rearward of the vehicle body. The rear upper portion 111b is located at an upper half 112a of a side member 112. Therefore, when a collision force is applied to the rear upper portion 111b of the rear bumper beam 111 as shown by arrow F, the rear bumper beam 111 can incline in the direction of arrow a. Consequently, a being moment can be applied to a rear end portion of the side member 112.
In addition, if the rear bumper beam 111 inclines in the arrow direction, the load acting on the rear bumper beam 111 will escape. It is, therefore, difficult to sufficiently absorb collision energy produced in a collision by the rear bumper beam 111.
Some vehicle bumper structures are required to absorb small collision energy in a collision at low speed (lower than or equal to about 8 km/hr) or the like.
It is therefore desirable to prevent application of a bending moment to a side member in a low-speed collision and appropriately absorb collision energy.